Hi, I'm trying to get my program to compile with ghc-9.8.2. Raising the upper bounds of my dependencies I'm running into a compile error for the unix-2.8.5.1 package: [15 of 53] Compiling System.Posix.Env.PosixString ( /home/dan/sources/unix-2.8.5.1/dist-newstyle/build/x86_64-linux/ghc-9.8.2/unix-2.8.5.1/build/System/Posix/Env/PosixString.hs, /home/dan/sources/unix-2.8.5.1/dist-newstyle/build/x86_64-linux/ghc-9.8.2/unix-2.8.5.1/build/System/Posix/Env/PosixString.o, /home/dan/sources/unix-2.8.5.1/dist-newstyle/build/x86_64-linux/ghc-9.8.2/unix-2.8.5.1/build/System/Posix/Env/PosixString.dyn_o ) System/Posix/Env/PosixString.hsc:45:1: error: [GHC-87110] Could not load module ‘System.OsString.Internal.Types’. It is a member of the hidden package ‘os-string-2.0.3’. Perhaps you need to add ‘os-string’ to the build-depends in your .cabal file. It is a member of the hidden package ‘filepath-1.4.200.1’. Perhaps you need to add ‘filepath’ to the build-depends in your .cabal file. Use -v to see a list of the files searched for. | 45 | import System.OsString.Internal.Types | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ System/Posix/Env/PosixString.hsc:47:1: error: [GHC-61948] Could not find module ‘System.OsString.Data.ByteString.Short’. Perhaps you meant System.OsString.Data.ByteString.Short (needs flag -package-id os-string-2.0.3) System.OsPath.Data.ByteString.Short (needs flag -package-id filepath-1.4.200.1) System.OsString.Data.ByteString.Short.Word16 (needs flag -package-id os-string-2.0.3) | 47 | import qualified "os-string" System.OsString.Data.ByteString.Short as B | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ System/Posix/PosixPath/FilePath.hsc:50:1: error: [GHC-61948] Could not find module ‘System.OsString.Data.ByteString.Short’. Perhaps you meant System.OsString.Data.ByteString.Short (needs flag -package-id os-string-2.0.3) System.OsPath.Data.ByteString.Short (needs flag -package-id filepath-1.4.200.1) System.OsString.Data.ByteString.Short.Word16 (needs flag -package-id os-string-2.0.3) | 50 | import "os-string" System.OsString.Data.ByteString.Short as BSS | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ System/Posix/PosixPath/FilePath.hsc:55:1: error: [GHC-87110] Could not load module ‘System.OsString.Internal.Types’. It is a member of the hidden package ‘os-string-2.0.3’. Perhaps you need to add ‘os-string’ to the build-depends in your .cabal file. It is a member of the hidden package ‘filepath-1.4.200.1’. Perhaps you need to add ‘filepath’ to the build-depends in your .cabal file. Use -v to see a list of the files searched for. | 55 | import System.OsString.Internal.Types (PosixString(..), pattern PS) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I can get rid of this compile error and a similar one for the directory package by setting the flag os-string in my cabal.project file: constraints: unix +os-string, directory +os-string Now I'm wondering what is the right way to handle this case? Thanks for any hints! Greetings, Daniel